In my experiments with photogrammetry, instead of step 7 to add texture, I have tried mixing two colors of kinetic sand. It works and give enough texture for ma

In my experiments with photogrammetry, instead of step 7 to add texture, I have tried mixing two colors of kinetic sand. It works and give enough texture for matching provided that the pictures are close-up enough,sharp and of high-resolution. I am always impressed by the ability of computer vision to match patches of similarly random textures. The texture of kinetic sand isn't great to hold shape for modelling, and the size of the sand grain is a little too small, which means you must take great care when taking the pictures. There is probably some room for a product in the market : a mixed-colored-clay with the right sized grain and texture for photogrammetry. One last question I have is, how do I unmix my kinetic sand to get the blue sand in the blue castle and the red sand in the red castle ? How long does it take before the kids mix all the colors when you buy them kinetic sand ? Is there some solvent for the paint I can put my sand in to get transparent sand, and then plunge it in some water based paint to get some color back ? Does different colors have different grain size so they can be separated by sieving ? Or is it just an educational tool to teach kids early about irreversibility ?